Seasonality of Cryptosporidium oocyst detection in surface waters of Meru, Kenya as determined by two isolation methods followed by PCR

Muchiri, John M.; Ascolillo, L.; Mugambi, M.; Mutwiri, Titus; Ward, Honorine; Naumova, Elena N.; Egorov, Andrey I.; Cohen, Stanley; Else, James G.; Griffiths, Jeffrey K.

doi:10.2166/wh.2009.109

Cited by 45 publications

(35 citation statements)

References 30 publications

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“…Endemic cryptosporidiosis has also been associated with the onset of the rainy season in Guinea Bissau (26), Uganda (29), Malawi (25), and Brazil (24). A recent study from Kenya also documented increased oocyst contamination of surface waters at the end of the rainy season, which was consistent with the timing of human infections in the region (20). However, cryptosporidiosis has been reported to occur in the spring season in South Korea (6), in the summer and autumn months in Israel (12), and in the cooler months of November to April in Kuwait (28).…”

Section: Discussionmentioning

confidence: 68%

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Multisite Study of Cryptosporidiosis in Children with Diarrhea in India

et al. 2010

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Cryptosporidium spp., a common cause of diarrhea in children, were investigated in the first multisite study in India. Diarrheal stools from hospitalized children aged <5 years from Delhi, Trichy, and Vellore were analyzed by microscopy, PCR-restriction fragment length polymorphism (RFLP), and/or sequencing at the small-subunit (SSU) rRNA and Cpgp40/15 loci for species determination and subgenotyping, respectively. Seventy of 2,579 (2.7%) children, 75% of whom were <2 years old, had cryptosporidial diarrhea as determined by microscopy. Genotyping and subgenotyping showed that Cryptosporidium hominis was the most commonly identified species (59/67 children), and subgenotypes Ie, Ia, Ib, and Id were common in all centers. A novel C. parvum subgenotype, IIn, was identified in Vellore. Meteorological analysis revealed a higher rate of cryptosporidial positivity during hotter and drier weather in Delhi.Cryptosporidium spp. are an important cause of endemic parasitic diarrhea in children in developing countries. In addition to causing symptoms associated with watery diarrhea, vomiting, and weight loss, early childhood cryptosporidiosis has been shown by studies to be associated with subsequent faltering of growth (reviewed in reference 11). Cryptosporidium hominis and C. parvum cause the majority of infections in children in developing countries, with C. hominis predominating and occasional reports of infection with zoonotic species such as C. felis, C. canis, C. meleagridis, and C. muris (30). C. hominis infection has been found to be associated with greater levels of oocyst shedding (4) and longer durations of oocyst shedding (31) and diarrhea (15) than C. parvum infection. In a recent community-based study in Vellore, we found increased levels of severity of diarrhea in C. hominis-infected children compared to the levels observed in children infected with other species (1).Cryptosporidium spp. have been classified into several distinct subgenotypes based on extensive polymorphisms in the Cpgp40/15 (also referred to as GP60) locus by use of PCRrestriction fragment length polymorphism (RFLP) or sequencing of PCR products (reviewed in reference 30).A number of studies from India have reported Cryptosporidium spp. in diarrheal stool samples from children, with positivity rates of up to nearly 20% (17) and asymptomatic infection rates of up to 10% (19), using stool microscopy for detection. However, only three studies have used molecular techniques for identification of cryptosporidiosis in children in India (9,13,22), suggesting that the actual infection rates may be significantly higher. In a previous hospital-based study in Vellore, we that found that PCR (15.2%) identified more than 3 times the number of cases of cryptosporidial diarrhea than microscopy (4.4%) (2). The aim of the present study was to identify the Cryptosporidium species and Cpgp40/15 subgenotypes associated with cryptosporidial diarrhea in hospitalized children from 3 centers in the country, since no studies have examined cryptosporidiosis using the...

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Section: Discussionmentioning

confidence: 68%

“…in their stool samples by microscopy. Children from Delhi showed a higher prevalence (34/970 [3.5%]) (P ϭ 0.055) than children from the 2 southern Indian centers in Vellore (20 25] months) (P ϭ 0.024). Most children were male (67.1%).…”

Section: Resultsmentioning

confidence: 99%

Multisite Study of Cryptosporidiosis in Children with Diarrhea in India

et al. 2010

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“…Purification by IMS, including identification by immunofluorescence assay (FA) recommended by the US-EPA method 1622 in 2001 has been widely used with recovery rates varying from 40.0 to 100% [5][6][7][8]10]. Apart from IMS, densitybased purification methods, such as sucrose floatation and Percoll-sucrose centrifugation were also applied for purifying oocysts from very turbid water samples [9,11,14]. In the present spiked water sample study, we found that sucrose floatation method enhanced with immunofluoresence assay (SF-FA) showed slightly higher purification efficiency than IMS-FA, especially in high turbidity waters.…”

Section: Discussionmentioning

confidence: 99%

Cryptosporidium Oocyst Detection in Water Samples: Floatation Technique Enhanced with Immunofluorescence Is as Effective as Immunomagnetic Separation Method

2009

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Abstract:Cryptosporidium can cause gastrointestinal diseases worldwide, consequently posing public health problems and economic burden. Effective techniques for detecting contaminated oocysts in water are important to prevent and control the contamination. Immunomagnetic separation (IMS) method has been widely employed recently due to its efficiency, but, it is costly. Sucrose floatation technique is generally used for separating organisms by using their different specific gravity. It is effective and cheap but time consuming as well as requiring highly skilled personnel. Water turbidity and parasite load in water sample are additional factors affecting to the recovery rate of those 2 methods. We compared the efficiency of IMS and sucrose floatation methods to recover the spiked Cryptosporidium oocysts in various turbidity water samples. Cryptosporidium oocysts concentration at 1, 10 1 , 10 2 , and 10 3 per 10 ml were spiked into 3 sets of 10 ml-water turbidity (5, 50, and 500 NTU). The recovery rate of the 2 methods was not different. Oocyst load at the concentration < 10 2 per 10 ml yielded unreliable results. Water turbidity at 500 NTU decreased the recovery rate of both techniques. The combination of sucrose floatation and immunofluorescense assay techniques (SF-FA) showed higher recovery rate than IMS and immunofluorescense assay (IMS-FA). We used this SF-FA to detect Cryptosporidium and Giardia from the river water samples and found 9 and 19 out of 30 (30% and 63.3%) positive, respectively. Our results favored sucrose floatation technique enhanced with immunofluorescense assay for detecting contaminated protozoa in water samples in general laboratories and in the real practical setting.

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“…In developing countries, there has been only one small-scale study in Kenya, in which Cryptosporidium oocysts in nine surface water samples were genotyped (36). Because the stringency of wastewater treatment and discharge and the intensity of animal husbandry are very different between developing countries and industrialized nations, observations made in the latter cannot be applied easily to the former.…”

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confidence: 99%

Occurrence, Source, and Human Infection Potential of Cryptosporidium and Giardia spp. in Source and Tap Water in Shanghai, China

Feng

Zhao

Chen

et al. 2011

Appl Environ Microbiol

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Genotyping studies on the source and human infection potential of Cryptosporidium oocysts in water have been almost exclusively conducted in industrialized nations. In this study, 50 source water samples and 30 tap water samples were collected in Shanghai, China, and analyzed by the U.S. Environmental Protection Agency (EPA) Method 1623. To find a cost-effective method to replace the filtration procedure, the water samples were also concentrated by calcium carbonate flocculation (CCF). Of the 50 source water samples, 32% were positive for Cryptosporidium and 18% for Giardia by Method 1623, whereas 22% were positive for Cryptosporidium and 10% for Giardia by microscopy of CCF concentrates. When CCF was combined with PCR for detection, the occurrence of Cryptosporidium (28%) was similar to that obtained by Method 1623. Genotyping of Cryptosporidium in 17 water samples identified the presence of C. andersoni in 14 water samples, C. suis in 7 water samples, C. baileyi in 2 water samples, C. meleagridis in 1 water sample, and C. hominis in 1 water sample. Therefore, farm animals, especially cattle and pigs, were the major sources of water contamination in Shanghai source water, and most oocysts found in source water in the area were not infectious to humans. Cryptosporidium oocysts were found in 2 of 30 tap water samples. The combined use of CCF for concentration and PCR for detection and genotyping provides a less expensive alternative to filtration and fluorescence microscopy for accurate assessment of Cryptosporidium contamination in water, although the results from this method are semiquantitative.

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Seasonality of Cryptosporidium oocyst detection in surface waters of Meru, Kenya as determined by two isolation methods followed by PCR

Abstract: Meru, Kenya has watersheds which are shared by wildlife, humans and domesticated animals.These surface waters can be contaminated by the waterborne pathogen Cryptosporidium. To quantify the seasonality and prevalence of Cryptosporidium in Meru regional surface waters, we

Cited by 45 publications

References 30 publications

Multisite Study of Cryptosporidiosis in Children with Diarrhea in India

Multisite Study of Cryptosporidiosis in Children with Diarrhea in India

Cryptosporidium Oocyst Detection in Water Samples: Floatation Technique Enhanced with Immunofluorescence Is as Effective as Immunomagnetic Separation Method

Occurrence, Source, and Human Infection Potential of Cryptosporidium and Giardia spp. in Source and Tap Water in Shanghai, China

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